US3727075A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Missing type detector
Assignee: International Business Machines Corp
•
Filing: 1972-02-24
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Granted: 1973-04-10
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Expires: 1992-02-24
Abstract
Abstract A moving train of type elements associated with a high speed printer are passed through the gap of an inductor. The inductor, which is part of a tank circuit of an oscillator, provides a magnetic field across the gap which induces eddy currents in the type elements. The oscillator provides an output signal which is responsive to the changes in the effective resistance of the inductor caused by changes in the eddy currents whenever at least a predetermined portion of at least one of the type elements is missing.
Inventors
- 👤 B Wolfe
- 👤 F Buckley
- 👤 G Melnyk
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:30
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/0703; G06F11/0751; G01; G01N; G01N27/00; G01N27/02; G01N27/023
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
118 words
In a moving type printer having a train of type elements moving in a predetermined path, missing type detector circuit apparatus comprising: oscillator circuit means having tank circuit means, and inductor means included in said tank circuit means, said inductor means having a gap through which said train of moving type elements pass, and said inductor means providing a magnetic field across said gap for inducting eddy currents in said moving type elements; and output signal means providing an output signal in response to changes in the effective resistance of said inductor means caused by the changes in said inducted eddy currents whenever at least a predetermined portion of at least one of said type elements is missing.
Claim 2
Dependent Claim
118 words
In a moving type printer having a train of type elements moving in a predetermined path, missing type detector circuit apparatus comprising: oscillator circuit means having tank circuit means, and inductor means included in said tank circuit means, said inductor means having a gap through which said train of moving type elements pass, and said inductor means providing a magnetic field across said gap for inducting eddy currents in said moving type elements; and output signal means providing an output signal in response to changes in the effective resistance of said inductor means caused by the changes in said inducted eddy currents whenever at least a predetermined portion of at least one of said type elements is missing.
Claim 3
Dependent Claim
117 words
Detector circuit apparatus according to claim 1 wherein said output signal means further comprises: comparator means having first and second input means and first output means for providing said output signal, peak detector means having third input means and second output means, said second output means being coupled to said first input means, means for coupling said third input means of said peak detector means to said tank circuit means, and reference signal means coupled to said second input means for providing a threshold reference signal thereat, said comparator means providing said output signal at said first output means whenever the peak follower''s output signal at said second output means is greater than the threshold reference signal.
Claim 4
Dependent Claim
43 words
Detector circuit apparatus according to claim 1 wherein said oscillator circuit means further comprises: an amplifier having input and output means associated therewith, and positive feedbAck means coupled between said input and output means, said positive feedback means comprising said tank circuit means.
Claim 5
Dependent Claim
55 words
Detector circuit apparatus according to claim 3 wherein said feedback means further comprises: a current amplifier for driving said tank circuit means, said current amplifier having control input means coupled to said output means, a feedback impedance network, and coupling means for coupling said feedback impedance network between said input means and said output means.
Claim 6
Dependent Claim
38 words
Detector circuit apparatus according to claim 4 wherein said coupling means further comprises buffer circuit means coupled between said tank circuit means and said feedback impedance network, said output signal means being coupled to said buffer circuit means.
Claim 7
Dependent Claim
122 words
Detector circuit apparatus according to claim 5 wherein said output signal means further comprises: comparator means having second and third input means and second output means for providing said output signal, peak detector means having fourth input means and third output means, said third output means being coupled to said second input means, said fourth input means being coupled to said buffer circuit means to effectuate the aforementioned coupling of said output signal means thereat, and reference signal means coupled to said third input means for providing a threshold reference signal thereat, said comparator means providing said output signal at said second output means whenever the peak follower''s output signal at said third output means is greater than the threshold reference signal.
Claim 8
Dependent Claim
17 words
Detector circuit apparatus according to claim 1 when said oscillator circuit means is of the narrow-band type.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |